Bearings subject to selected axial preload
(light [L], medium [M] or heavy [F]) and having flush side
faces under preload are classed as Universal [U].
SNFA universal bearings have the suffix UL, UM, UF according
to the required preload and offer users the possibility of
forming groups of bearings in any required arrangement (DD,
FF or T) by using their own stock, without having to make
any ring face adjustment.
As a consequence of their manufacturing features, the resultant
preload of groups of U bearings is obtained by multiplying
the preload of the single U bearing by the following coefficients:
 Sets
Coefficient
DD –
FF 1.00
TD –
TF 1.35
3TD - 3TF1.60
TDT –
TFT 2.00
Above mentioned sets formed with “Universal”
bearings, when compared to the “SNFA matched sets”,
offer advantage for stocking requirements but their contact
angle and bore/outer diameter tolerance do not maintain SNFA
standards.
A variant, consisting of Duplex Universal bearings, coded
DUL, DUM and DUF according to preload, is also available.
Its advantages can be summarized below:
- the bearings of the same pair can be mounted in any configuration
(DD, FF or T)
- the contact angle difference between the two bearings
is minimum (a significant advantage for a tandem configuration)
- the difference in the actual bore and outside diameter,
between the two bearings, is minimal (one third of overall
tolerance)
- Universal Duplex bearings from different sets may not
exchanged between each other.
The speed, preload and rigidity values indicated in the bearing
table refer to SNFA matched bearings. For asymmetrical groups
(TD – TF), formed by single Universal bearings, these
values must be calculated for each case, taking proper account
of the preload correction coefficients mentioned above.
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Product Desc.